The present invention relates to impact rock rippers and pertains particularly to cooling means for the cutting tip of such rippers.
Mechanical rippers have been used for cutting and ripping relatively soft weathered layered or previously blasted rocks. However, such rippers have not been efficient or useful in ripping hard rocks and pavement or the like.
One of the major problems with the use of such rippers is the high forces that must be induced in rock and similar hard material to cause it to fracture. This necessitates the delivery of very high forces and energy to the face of the rock or other material to be fractured or separated. Mechanical impact rippers, which are capable of delivering very high forces to the tip of such rippers has been recently developed. Rippers of this type are covered, for example, in U.S. Pat. No. 3,770,322, issued Nov. 6, 1973 to Cobb, et al. and entitled "Apparatus for Fracture of Material in Situ with Stored Inertial Energy."
Because of the very high energies delivered to the point of such rippers and the very high speeds of the ripper tip upon the delivery of energy thereto excessive heat and wear to the ripper tip becomes a major problem. The supplying of a coolant to the ripper tip presents a problem of how to effectively supply sufficient coolant to the tip in a reliable manner. The placement passages in the tip itself can weaken it and result in early failure of the tip for that reason. Also, the positioning of the orifices for supplying the liquid to the surface of the tip must be so located to supply the liquid to the proper areas of the surface. Also, such openings must be so located as to avoid the problem of clogging of the passages.
An example of the prior art approach to the supplying of a liquid to a cutting blade, is shown in U.S. Pat. No. 3,685,592, issued Aug. 22, 1972 to Claude M. Frisbee and entitled "Fluid Cushioned Dozer Blade". In that patent a liquid of fluid film is supplied to the front surface of a dozer blade to reduce friction and prevent the adhesion of soil to the moldboard portion of the blade.
Other patents known to the applicant which are for the purpose of supplying a liquid behind a blade are as follows: U.S. Pat. No. 2,713,299, issued July 19, 1955 to Shager, et al.; U.S. Pat. No. 2,988,026, issued June 3, 1961 to Heckathorn; and U.S. Pat. No. 3,294,181, issued Dec. 27, 1966 to Binder. These three patents are directed to the problem of distributing a liquid fertilizer or the like in a furrow behind an agricultural plow blade. They are not concerned with the problem of cooling the cutting blade or tip.
A system for supplying water to drum-type rotary coal cutters is disclosed by U.S. Pat. No. 3,827,755, issued August 6, 1974 to Allen.